No,_____you have finished doing the dishes.

问题描述:

No,_____you have finished doing the dishes.
A.unless B.if C.because D.when
好像是选A,但是不明白为什么后半句的do要+ing?求讲解语法
—May i surf the internet now?
—No,_____you have finished doing the dishes.

选A,finish 后要接ing